A rail anchor clamps onto a rail and is positioned to abut a vertical face of a tie whereby there is resistance to longitudinal movement of the rail relative to the supporting tie.
For many years, there have been machines for setting and applying rail anchors. This type of equipment is shown in Quella Patent No. 4,890,558 and Miller Patents Nos. 3,117,530 and 3,132,597. Additional equipment of this type is shown in McIlrath Patents Nos. 3,272,148 and 3,438,335. Equipment for applying a clip, rather than an anchor, is shown in McIlrath Patent No. 4,320,707.
The foregoing equipment result in placing rail-mounted anchors in close abutting relation with opposite vertical faces of a tie. When a tie is to be replaced, it is necessary to shift the tie-abutting, rail-mounted anchors lengthwise of the rail to positions away from the tie, so that a tie remover can longitudinally withdraw the tie from beneath the rail, followed by tie replacement and return of the rail-mounted anchors to tie-abutting positions. This return of the anchors to tie-abutting positions could be accomplished by use of a rail anchor relocator, such as shown in the Miller Patent No. 3,117,531.
In spreading a pair of anchors along a rail, the forces required to spread each anchor may not necessarily be equal and opposite, which could result in an imbalance of forces tending to move the anchor spreader, itself, longitudinally of the rail. If the anchor spreader is operating against only a single anchor, an even greater force imbalance is created. Therefore, it is desirable for the spreader to have the capability of fixedly engaging the rails prior to spreading the anchors. In this way the reaction force is transmitted to the rails and the spreader is not shifted It also is critical, however, to avoid damaging or deforming the rail when clamping Rail deformation produces local stress risers in the rail which would eventually lead to catastrophic failure under the extreme loadings to which they are exposed. Prior spreader devices, though successful for many years, do not disclose such a damage-free rail engaging capability.